             ready
             (atom #{})
 
-            ;; files that were actually compiled (not recycled)
-            compiled
-            (atom [])
-
             ;; source-name -> exception
             errors
             (atom {})

            (let [{:keys [provides] :as compiled-src}
                  (generate-output-for-source state src)]

              (when (not= (:compiled-at src)
                          (:compiled-at compiled-src))
                (swap! compiled-ref conj source-name))

              (swap! ready-ref set/union provides)
              compiled-src)
            (catch Exception e

        (fn [state source-name]
          (let [src (get-in state [:sources source-name])
                compiled-src (generate-output-for-source state src)]
            (assoc-in state [:sources source-name] compiled-src)))
        state
        source-names))))

(defn par-compile-one
  [state ready-ref errors-ref source-name]
  (let [{:keys [requires] :as src}
        (get-in state [:sources source-name])]

